JP2540127B2 - Programmable controller failure diagnosis device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a failure diagnosis device suitable for a building block type programmable controller.

<< Summary of the Invention >> According to the present invention, the system can be constructed by simply connecting a new failure diagnosis device to an existing programmable controller of a building block type, without creating a special failure diagnosis program on a user program. The failure of can be diagnosed.

<< Conventional Technology and Its Problems >> Conventionally, in the failure diagnosis of a programmable controller of this kind, a method in which the user himself / herself examines the input / output conditions that may occur at the time of failure and incorporates this into a user program is taken into consideration. It is extremely troublesome to add a failure diagnosis program to a user program that requires complicated work such as setting conditions and programming, especially when there is already a completed user program.

<Object of the Invention> An object of the present invention is that, in this type of programmable controller, it is not necessary for the user to create a failure diagnosis program, and it can be easily applied to an existing programmable controller system. Another object of the present invention is to provide a programmable controller failure diagnosis device capable of efficiently performing failure diagnosis of an input / output device in a programmable controller system without enormous capacity of a memory for storing an input / output pattern.

<< Structure and Effect of the Invention >> In order to achieve the above-mentioned object, the present invention provides a mode setting means capable of switching and setting an operation mode between a teaching mode and a diagnostic mode, and a programmable
Teaching operation control means for monitoring the output pattern of the controller and storing the elapsed time from the previous change time and the input / output pattern after the change each time the output pattern changes, and the condition for setting to the diagnostic mode As programmable
The output pattern of the controller is monitored, and it is determined whether or not the output pattern stored in the teaching operation control means comes within the monitoring time based on the elapsed time stored corresponding to the output pattern. When the output pattern stored in the teaching operation control means does not arrive within the monitoring time, the mismatching portion between the input / output pattern at that time and the input / output pattern stored in the teaching operation control means is notified. And a diagnostic operation control means.

With this configuration, the failure diagnosis program is automatically created in response to the setting to the teaching mode, while the failure diagnosis operation independent of the CPU unit is performed in response to the setting to the diagnosis mode. Therefore, it is not necessary for a user to create a failure diagnosis program, and failure diagnosis of an input / output device in this type of system can be performed without changing the existing user program.

Further, in the present invention, since the failure diagnosis program is created by paying attention to the change of only the output pattern, not the input pattern of the programmable controller, the capacity of the memory for storing the input / output pattern does not become huge and the efficiency is improved. In addition, it is possible to diagnose failures of input / output devices in the programmable controller system.

This is because when the input / output pattern is sampled by capturing the change in the input pattern, there are various types of input signals of the programmable controller, such as analog input and relay input. The transition does not always repeat in the same state every cycle, and it is difficult to diagnose failures of input / output devices, and when a counter instruction is used in the user program, calculate the number of inputs and output. The control such as passing to be used is frequently performed on a daily basis. In this case, if the change in the input pattern is captured and processed, the number of changes is too large, and the memory capacity for storing the input / output pattern is enormous. However, since the present invention focuses on the change in the output pattern of the programmable controller, such a problem occurs. There is no.

<< Description of Embodiments >> FIG. 1 is a block diagram showing the overall configuration of a building block type programmable controller to which the present invention is applied.

As shown in the figure, the system includes a system bus 1, a CPU unit 2, a plurality of I / O units 3, 3, ... And a failure diagnosis device according to the present invention (hereinafter, referred to as "failure diagnosis unit").
Say. ) 4 are connected. The power supply unit and others are omitted.

As shown in FIG. 2, the failure diagnosing unit 4 includes a computing unit 41 mainly composed of a microprocessor, a storage unit 42 mainly composed of a RAM, and a timing unit 43 mainly composed of a reference clock, a counter and the like. The display unit 44 is capable of displaying the input / output corresponding to the failure correlation point and the occurrence of the failure, and the operation section 45 having a mode changeover switch, a start switch and the like. In addition, the calculation unit 41 is an interface
It is possible to connect to the system bus 1 via 46.

As shown in the general flow chart of FIG.
The operation of the failure diagnosis unit 4 depends on whether the mode selector switch of the operation unit 45 is set to the teaching mode (step 300
Affirmative) or whether the diagnosis mode is set (Yes at Step 301), the teaching operation control process (Step 3
02) and the diagnostic operation control process (step 303) are selectively executed.

As shown in FIG. 4, when the teaching motion control process is started, first, a state of waiting for the activation switch of the operation unit 45 being turned on (activation signal “1”) is set (step 400).
Denial, 401 Denial).

When the start switch is turned on (Yes at Step 400, 402
Yes, after resetting the STEP counter to zero (step 40
3), I / O patterns I _{1 to} In and O _{1 to On} at the time point are registered in the storage area related to 0STEP (step 404), and the elapsed time is 0.
Is registered (step 405), the STEP counter is updated by +1 (step 406), and the elapsed time measuring clock is activated (step 407).

At this time, the input / output pattern is registered by directly reading the data of the I / O unit 3 into the failure diagnosis unit 4 or by synchronizing the input / output information during the input / output update operation performed by the CPU unit 2. It is done by incorporating.

After that, the arithmetic unit 41 repeatedly reads the output pattern and waits for a change (step 400, Yes,
402 denial, 408 denial).

In this state, the output pattern changes, that is, the output
When any one bit of O ₁ to On changes (Step 40
8), the storage area specified by the STEP counter,
After the registration of the changed input / output pattern (step 409) and the registration of the elapsed time from the previous change time (step 410), the STEP counter is updated by +1 (step 41).
1) After the operation of restarting the elapsed time measurement clock from zero (step 412), the output pattern change waiting state is again entered (step 400 positive, 402 negative, 408 negative).

As a result, in each area designated by the STEP counter in the storage unit 42, each time the output pattern changes, the changed input / output pattern and the elapsed time from the immediately preceding change time are sequentially stored. Becomes

Next, when the activation switch is turned off in the operation unit 45 (No at Step 400, Yes at 401), the input / output pattern is registered in the storage area designated by the STEP counter (Step 41).
3), Register the elapsed time from the previous change point (step 41
After 4), all registration operations are completed.

Therefore, assuming a user program in which only the inputs 1 and 2 and the output 1 change as shown in FIG. 6, the output I changes at the times t ₁ and t ₁₀ as a result, and as shown in FIG. As shown in the table, the changed input / output pattern and elapsed time are sequentially stored in the storage area corresponding to each STEP in the storage unit 42.

Next, when the mode selector switch is set to the diagnostic mode on the operation unit 45, the diagnostic operation control process is started.

As shown in FIG. 5, in the diagnostic operation control process, first, the start-up switch is on standby (step 50).
0 negative, 501 negative).

When the activation switch is turned on (Yes at Step 500, 505
Yes, after resetting the STEP counter to zero (step 50)
3), diagnostic operation is started.

In this diagnostic operation, first, an operation of setting the input / output pattern registered in the current STEP as a reference pattern (step 504), and a monitoring timer using the value obtained by multiplying the elapsed time registered in the current STEP by a system constant as the reference time. After the operation of setting to (step 505), the monitoring timer is started (step 506), and thereafter, before the monitoring timer expires, it waits until the current output pattern and the reference output pattern match (No at step 507). , 510 denied).

Then, before the monitoring timer expires (step 51
0 negative), if it is confirmed that the current output pattern and the reference output pattern match (Yes in step 507), the abnormal output is turned off,
After clearing abnormal point data (step 508), STE
The P counter is updated (step 509) and the above operation is repeated for the next STEP.

On the other hand, if the match between the current output pattern and the reference output pattern is not confirmed before the time-out of the monitoring timer, it is determined that the system is out of order, and when the time-out of the monitoring timer occurs (Yes at Step 510). ), The exclusive OR (EOR) of the current input / output pattern and the reference input / output pattern is taken, and the result is set as abnormal point data (step 511), and with the abnormal output ON (step 512), the display unit 44 Is displayed in.

As a result, the display section 44 visually informs a mismatched portion between the current input / output pattern and the reference input / output pattern as a failure correlation portion, and detects which one of the input / output devices connected to this programmable controller. It is possible to quickly recognize whether a device has a failure.

As described above, in this embodiment, the input / output pattern at the time of normal operation is registered as shown in FIG. 7 only by setting the mode changeover switch to the teaching mode and turning on the start switch, and then the mode changeover switch. The failure of the system can be surely diagnosed thereafter by simply setting the teaching mode to the teaching mode and turning on the start switch.

Therefore, unlike the conventional failure diagnosis, the user does not need to analyze the input / output conditions at the time of failure and incorporate it into the user program, and the failure diagnosis unit 4 operates independently of the CPU unit 2. There is no fear of delaying the circuit operation processing operation in the above.

Therefore, the present invention can be easily applied to an existing building block type programmable controller system.

[Brief description of drawings]

FIG. 1 is a block diagram showing an entire building block type programmable controller system to which the present invention is applied, FIG. 2 is a block diagram showing details of a failure diagnosis unit, and FIG. 3 is a general flowchart of the failure diagnosis unit. FIG. 4 is a flowchart showing details of the teaching operation control processing, FIG. 5 is a flowchart showing details of the diagnostic operation control processing, FIG. 6 is an explanatory view showing an example of transition of input / output patterns, and FIG. It is a memory map showing the contents. 1 ... System bus 4 ... Fault diagnosis unit

Continuation of the front page (56) Reference JP-A-59-218523 (JP, A) JP-A-58-222310 (JP, A) JP-A-60-160447 (JP, A) JP-A-60-146303 (JP , A) JP 59-158410 (JP, A) JP 60-122407 (JP, A)

Claims (1)

(57) [Claims] 1. A mode setting means capable of switching and setting an operation mode between a teaching mode and a diagnostic mode; the output pattern of a programmable controller is monitored under the condition of setting to the teaching mode, and a change in the output pattern is monitored. Teaching operation control means for storing the elapsed time from the immediately preceding change time and the input / output pattern after the change each time; and the teaching operation by monitoring the output pattern of the programmable controller under the condition of setting to the diagnostic mode. It is determined whether the output pattern stored in the control means comes within the monitoring time based on the elapsed time stored corresponding to the output pattern, and the output pattern stored in the teaching operation control means. Is not received within the monitoring time, the input / output pattern at that time and the input / output pattern stored in the teaching operation control means are stored. Programmable controller of the failure diagnosis apparatus characterized by comprising; and diagnosing operation controlling means for informing mismatch position and force pattern.